I'm a 20-year-old guy and I've been dealing with this phlegm or mucus issue in my lungs. Its been more than a month now, and whenever I cough to spit it out, it just keeps coming back. The stuff I spit out is sticky and has some white in it. I havent seen a doctor about this yet, and Im kind of worried. Can you tell me what might be going on and what I should do about it?